The present invention relates to a display apparatus wherein three primary color images are successively or sequentially displayed in a short period of time and recognized as a full-color image by an observer.
As a display apparatus, a liquid crystal apparatus has been used in various equipment, such as personal computers, and in recent years, the liquid crystal apparatus has been desired to be adapted for color display.
As one scheme for effecting color display, as shown in FIG. 4, a scheme wherein one frame period (F1, F2, . . . ) is equally divided into three periods in which three color images of red (R), green (G) and blue (B) are successively displayed in a short period of time (i.e., in each of the three periods), respectively, and the resultant color images are memorized in human eyes as an afterimage, thus causing the observer to recognize the afterimage as a full-color image for each frame period (hereinafter, referred to as xe2x80x9cthree primary color sequential display schemexe2x80x9d) has been proposed.
According to this scheme, the resultant liquid crystal apparatus has the advantages of an increase in apparent resolution by about three times an ordinary liquid crystal apparatus using color filters, a reduction in production costs since the apparatus is not required to use color filters and an increase in an aperture (opening) ratio by about three times the ordinary liquid crystal apparatus to lower a power consumption.
However, in such a liquid crystal apparatus according to a three primary color sequential display scheme, any one of the color images (R, G, B) is always displayed. As a result, in the case of motion (moving) picture display, image qualities of a full-color image recognized in a frame period F1 just before the frame period F2, i.e., deteriorated by the influence of an afterimage phenomenon such that the color images of R, G and B in the preceding frame period F1 are left as an afterimage still in the frame period F2.
More specifically, referring to FIG. 4, the last color image (B) in the frame period F1 is liable to overlap with the first color image (R) in the subsequent frame period F2, thus failing to obtain a desired hue in the frame period F2 (color drift or shift). Further, in the case where a color of a prescribed color value (e.g., white) is displayed based on the three color images (R, G, B) in the frame period F1 and another color of a different color value (e.g., black) is displayed based on those in the subsequent frame period F2, a desired color value is not obtained in the frame period F2 in some cases, thus resulting in gray display state under the influence of the white color image in the preceding frame period F1 (image blur).
An object of the present invention is to provide a display apparatus capable of preventing deterioration in image qualities even in the case of motion picture color display.
According to the present invention, there is provided a display apparatus, comprising:
an optical modulation device including a plurality of pixels and a pair of electrodes to which a voltage is applied,
an illumination device for illuminating the optical modulation device instantaneously and successively with a plurality of monochromatic lights of different colors in a prescribed period to provide a full-color image in combination with application of the voltage to the electrodes of the optical modulation device thereby effecting a full-color display over a succession of the prescribed period, and
control means for dividing each prescribed period into two periods including a first period for displaying a full-color image at each pixel and a second period immediately after the first period and for placing the optical modulation device in a non-display state.
Herein, the term xe2x80x9cinstantaneouslyxe2x80x9d means a sufficient short period of time to the extent that an observer visually recognizes the color light illumination state as a state such that the color lights are apparently continuously turned on and are not recognized as a succession of a lighting-on state and a lighting-off state.
This and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.